public class OOS {

    public static void main(String[] args) {
        String s1 = "12";
        String s2 = "34";
        String s3 = "12";
        String s4 = s1 + s2;
        String s5 = "1234";
        String s6 = new String("12");

        System.out.println(s1 == s3);
        System.out.println(s1.equals(s3));
        System.out.println(s1 == s6);

        System.out.println(s4  == s5);
    }
}
